The trial involving Mattel Inc. and MGA Entertainment kicked off Tuesday, with Mattel saying MGA hid the origin of its wildly popular Bratz dolls for seven years and subsequently hurt Mattel’s Barbie sales.

A Mattel attorney said Tuesday in a Riverside courtroom that Van Nuys-based MGA for three years told conflicting stories about the origins of the dolls that have become the hallmark of the company. Former Mattel employee, Carter Bryant, created the line of dolls and secretly took his drawings to MGA, attorney John Quinn claimed in his opening statement according to an account from Bloomberg news.

Mattel can land up to hundreds of millions of dollars if the jury finds that the inspiration for the Bratz dolls came from a Mattel employee. Mattel said in court papers that MGA makes about $500 million a year off the edgy doll line.

Quinn continued by saying the evidence will show that Bryant was inspired by a Mattel Toon Teens design he saw in 1999. The designer put false dates on drawings he took to MGA to make it appear he made them in 1998, the lawyer said.

Bryant, who was originally in the case against Mattel, settled with the El Segundo-based Mattel for undisclosed terms. He’s listed as a witness for both sides in the trial.